For six millennia we humans have deliberately manipulated genes; modern corn is as distantly related to its wild ancestor as a Chihuahua is to a wolf.

In 1944, American biologist Norman Borlaug began 30 years in Mexico developing new strains of wheat. Borlaug crossed stubby-stalked dwarf wheat with high-yielding varieties. This resulted in a plant that was both extremely productive and strong enough to hold up a large cluster of grain as long as it was well fertilized.

After Borlaug’s new wheat increased the productivity of Mexican wheat sixfold, agronomists bred ‘semi-dwarf’ rice plants. The world went from food shortage to food surplus even as the postwar global population doubled.

This Green Revolution depended on mechanization, irrigation, petroleum-based fertilizers and drastic increases in the use of pesticides. Meanwhile giant corporations arose to produce hybrid seeds that farmers had to buy instead of using seeds from their crops. Many farmers could not compete and sold to the corporations.

Some decried the Green Revolution from the beginning for spreading ecologically destructive and unsustainable agricultural practices globally.

Supporters noted that the Green Revolution saved hundreds of millions of lives, mostly in nations where population growth outpaced food production.

Both arguments are correct and still valid. History has been driven by the thirst for natural resources whether they are energy, food, minerals or water. We are not the first to face the double-edged sword of consumption versus environment. We are the first to do it on a global scale.

World population more than doubled in the last half of the 20th century as the Green Revolution more than doubled food production and resource usage increased more than fourfold.

In the past decade we have become aware that the genome is not static, but rather a dynamic structure that communicates with its environment while continually refining its gene pool.

Ecologists tend to have reservations about transgenic crops because they realize how plants grow and interact outside the lab in concert with the environment, as opposed to molecular biologists, who tend to have a sharper focus on what happens inside the lab.

Widespread use of only a few varieties of transgenic crops runs the risk of lowering the diversity that is an essential element of a healthy ecosystem. When pests or other hazards to which the GMOs are not resistant arrive, as they certainly will, the transgenic varieties might not survive. On the other hand, contamination and crossbreeding with native crops is a real and serious possibility.

People must be fed, and transgenic crops may or may not, should or should not result in a second Green Revolution. Critics also assert that GMO crops have not been proved universally safe. This criticism is without validity since nothing can be proved scientifically. Science is a process of verification and disproof, not one of proof.

Yet decades of research have failed to find conclusive evidence that GMOs are a health risk.

Einstein famously said that no amount of testing could prove his theory of relativity to be correct, but only one result could prove it incorrect.

Richard Brill is a professor of science at Honolulu Community College. His column runs on the first and third Friday of the month. Email questions and comments to brill@hawaii.edu.